<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    *{
        padding: 0px;
        margin: 0px;
    }
    .haha{
        width: 0px;
        height: 0px;
        border: 30px solid black;
        border-color: black transparent transparent transparent;
    }
</style>
<body>
    <div class="haha">

    </div>
</body>
</html>